Physical activity and mental health

With strong evidence to show that most of us feel mentally better if we take exercise, there's clearly a positive relationship between physical activity and mental health - but what's responsible for it? In this article, Diane Crone summarises the theories that have been developed by researchers to explain how it works. She then reviews the research that has asked exercisers for their own opinions about what makes the difference for them and concludes with some practical advice for people using or providing exercise opportunities.